JP4676430B2 - Wafer storage container - Google Patents

Description

  The present invention relates to a wafer storage container for storing semiconductor wafers one by one, and more particularly to a technique for reducing particles adhering to a semiconductor wafer surface during storage.

Generally, since it is necessary to keep the surface clean, semiconductor wafers are stored or transported in a state in which they are stored in a wafer storage container.
As the wafer storage container, for example, a storage container disclosed in Patent Document 1 is used. FIG. 6 is a perspective view schematically showing a conventional semiconductor wafer storage container, and FIG. 7 is a cross-sectional view thereof.

  As shown in FIGS. 6 and 7, the wafer storage container 10 is disposed between a wafer accommodating member 11 having a dome-shaped recess 11 a capable of holding a wafer W, a lid member 12, and between the wafer W and the lid member 12. And a pressing member 13.

  The wafer accommodating member 11 and the lid member 12 are made of, for example, polypropylene, and the wafer accommodating member 11 and the lid member 12 are engaged to seal the wafer accommodating portion. The semiconductor wafer W is disposed in the dome-shaped recess 11a of the wafer accommodating member 11 with the wafer surface W1 facing downward, and is held in contact with the dome-shaped recess 11a at the peripheral edge of the wafer. It is possible to prevent particles from adhering due to contact with the members.

  The pressing member 13 has a plurality of leg portions 13b that are ejected outward from the central portion 13a. The central portion 13a and the leg portions 13b are formed to be curved as a whole, and cross the central portion 13a and the leg portion 13b. The cross section is arcuate. In addition, the pressing member 13 has a displacement between the center portion 13a and the tip of the leg portion 13b between the wafer back surface W2 and the inner wall surface 12a of the lid member 12 when the lid member 12 is engaged with the wafer housing member 11. It is shaped to be larger than the height of the space to be formed. Therefore, when the wafer accommodating member 11 and the lid member 12 are engaged, the central portion 13a is pushed by the lid member 12, and the peripheral edge portion of the wafer back surface W2 is pushed by the tip of the leg portion 13b.

  Although the semiconductor wafer is accommodated in the wafer storage container 10 having the structure described above, the lid member 12 and the wafer accommodation member 11 are not sealed using a seal member or the like so as to be easily handled. It is impossible to completely avoid the entry of particles. Further, particles may remain in the space inside the wafer storage container, or particles may be newly generated due to deterioration of the wafer storage container 10 itself.

Therefore, when the semiconductor wafer is stored in the wafer storage container for a long time, particles may adhere to the front and back surfaces of the semiconductor wafer. Therefore, in general, a wafer storage container containing wafers is packed with a laminate bag, and the inside of the laminate bag is evacuated and filled with an inert gas, and the laminate bag is sealed to prevent contact with outside air. Prevents particles from entering the wafer storage container. Specifically, a wafer storage container containing a semiconductor wafer is placed in a laminate bag having a high gas barrier property (for example, an aluminum laminate bag), the laminate bag is placed in a vacuum chamber, the inside of the chamber is depressurized, and then the inside of the chamber is placed. An inert gas such as nitrogen is introduced, and the laminate bag is hermetically sealed by thermocompression of the mouth of the laminate bag with a heater in the chamber.
Japanese Patent Publication No. 48-28953

  However, in the above-described wafer storage method, it is unlikely that particles will enter the wafer storage container after the wafer storage container is packaged and sealed with a laminate bag. There is a risk of entering. For example, since the wafer storage container is placed in the vacuum chamber and then depressurized by a vacuum pump and an inert gas is introduced into the chamber, a flow of air is generated. It is conceivable that particles enter the wafer storage container from the 11 engaging portions.

  Also, since semiconductor wafers usually have an orientation flat at the peripheral edge and are not completely circular, particles that enter the wafer storage container are removed from the gap between the semiconductor wafer and the dome-shaped recess of the wafer container. It may wrap around the wafer surface and adhere to the wafer surface. In such a case, if the semiconductor wafer is taken out from the wafer storage container and directly subjected to epitaxial growth or the like on the surface of the semiconductor wafer, abnormal growth or the like may occur. For this reason, since it is necessary to clean the wafer surface as a pre-process of epitaxial growth, there is a problem that the process becomes complicated.

  That is, when packaging the wafer storage container with the laminate bag, it is important to prevent the particles from entering the storage container or to prevent the particles entering the storage container from adhering to the semiconductor wafer (particularly the surface). .

  The present invention relates to a wafer storage container for storing semiconductor wafers one by one, and an object thereof is to provide a technique capable of effectively reducing the adhesion of particles to the surface of a semiconductor wafer being stored.

  The present invention has been made to solve the above problems, and is a wafer storage container for storing wafers one by one, and a wafer having a dome-shaped recess capable of holding a wafer in contact with the peripheral edge of the wafer A housing member and a lid member that can be engaged with the wafer housing member to seal the wafer housing portion, and is molded into substantially the same shape as the opening of the dome-shaped recess, and is formed in the dome-shaped recess. A wafer back surface protection member that is in close contact with the entire back surface of the wafer placed with the front surface facing is provided.

  As a result, when the semiconductor wafer is accommodated in the wafer storage container, the storage container is packed with a laminate bag, and the inside of the bag is replaced with an inert gas, an air flow is generated and particles enter the wafer storage container. However, since the particles are captured by the wafer back surface protection member, the particles do not adhere to the back surface of the semiconductor wafer. In addition, by molding the wafer back surface protection member into substantially the same shape as the opening of the dome-shaped recess of the wafer housing member, particles do not go around the wafer surface from the gap generated at the orientation flat position. Particles do not adhere to the surface.

  A holding member that is disposed between the wafer back surface protection member and the lid member and is pressed by the lid member when the wafer housing member and the lid member are engaged to press the wafer against the wafer housing portion; I prepared. For example, a member whose cross-sectional shape is an arcuate shape or a member having an elastic body sandwiched between an upper surface portion and a bottom surface portion can be used. At this time, the part pressed by the pressing member may be the entire surface of the back surface protection member or a part of the peripheral edge. Thereby, while being able to fix a wafer to a wafer accommodating member, the adhesiveness of a wafer back surface and a wafer back surface protection member can be improved.

  Alternatively, the wafer back surface protection member has a function as a pressing member that is pressed by the lid member when the wafer housing member and the lid member are engaged, and presses the wafer against the wafer housing portion. Also good. For example, it can be realized by providing an elastic member such as a leaf spring on the surface of the wafer back surface protection member opposite to the surface in close contact with the wafer.

  Further, a wafer surface protection member is provided between the wafer and the wafer housing member, in close contact with the dome-shaped recess, and in contact with the peripheral edge of the wafer. In order to prevent particles from being generated due to friction or the like due to contact between the wafer surface and other members, the wafer peripheral surface is held by the dome-shaped recess of the wafer housing member. The surface is open. However, for this reason, a larger space is formed on the front surface side of the semiconductor wafer than on the rear surface side of the wafer where the normal pressing member is inserted, and particles are likely to remain. Therefore, by providing a wafer surface protection member, the space formed between the semiconductor wafer and the dome-shaped recess is reduced.

  Further, the wafer back surface protection member and the wafer surface protection member are made of a material that is less likely to generate particles such as polyethylene, polypropylene, polyester, or vinyl chloride. Thereby, it can avoid that a particle generate | occur | produces from protection member itself and adheres to a semiconductor wafer.

  The wafer back surface protection member and the wafer surface protection member are preferably formed of a material with a small amount of released gas, such as a fluorine-based resin (for example, PTFE). As a result, it is possible to prevent the semiconductor wafer from being contaminated by the outgas generated from the protective member itself and deteriorating the quality of the wafer.

  According to the present invention, when a semiconductor wafer is accommodated in a wafer storage container, the storage container is packaged with a laminate bag, and the inside of the bag is replaced with an inert gas, an air flow is generated and particles are generated in the wafer storage container. Even if it enters, particles can be prevented from adhering to the front and back surfaces of the semiconductor wafer and contaminated, so that the surface of the semiconductor wafer can be kept clean for a long time. Therefore, the semiconductor device manufacturer can take out the semiconductor wafer from the wafer storage container and perform epitaxial growth on the surface of the semiconductor wafer as it is. Therefore, it is necessary to clean the wafer surface as a pre-process of epitaxial growth. There is an effect that productivity can be improved.

It is a perspective view showing the outline of the storage container of the semiconductor wafer concerning a 1st embodiment. It is sectional drawing of the storage container of the semiconductor wafer which concerns on 1st Embodiment. It is a perspective view which shows the outline of the storage container of the semiconductor wafer which concerns on 2nd Embodiment. It is sectional drawing of the storage container of the semiconductor wafer which concerns on 2nd Embodiment. It is an example of the wafer back surface protection member which gave the function of the pressing member. It is a perspective view which shows the outline of the conventional wafer storage container. It is sectional drawing of the conventional wafer storage container.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Wafer storage container 11 Wafer accommodating member 11a Dome-shaped recessed part 12 Cover member 13 Holding member 13a Center part 13b Leg part 14 Wafer back surface protection sheet (wafer back surface protection member)
15 Wafer surface protection sheet (wafer surface protection member)
W Semiconductor wafer

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a perspective view schematically showing a semiconductor wafer storage container according to the first embodiment, and FIG. 2 is a sectional view thereof.
As shown in FIGS. 1 and 2, the wafer storage container 10 is disposed between a wafer accommodating member 11 having a dome-shaped recess 11 a capable of holding a wafer W, a lid member 12, and between the wafer W and the lid member 12. And a pressing member 13. Furthermore, in the present embodiment, when the wafer surface W1 is disposed toward the dome-shaped recess 11a, the wafer is disposed between the wafer W and the pressing member 13 and serves as a wafer back surface protection member that is in close contact with the entire surface of the wafer back surface W2. A back surface protection sheet 14 is provided.

  The wafer accommodating member 11 and the lid member 12 are made of, for example, polypropylene, and the wafer accommodating member 11 and the lid member 12 are engaged to seal the wafer accommodating portion. The semiconductor wafer W is disposed in the dome-shaped recess 11a of the wafer housing member 11 with the wafer surface W1 facing downward, and is held in contact with the dome-shaped recess 11a at the peripheral edge of the wafer.

  The wafer back surface protection sheet 14 is made of a fluororesin film having a thickness of 100 μm, is molded in substantially the same shape as the opening of the dome-shaped recess 11a of the wafer housing member, and is adhered to the entire surface of the semiconductor wafer back surface W2. The entire surface of the opening of the dome-shaped recess 11a is covered. That is, the gap with the wafer housing member 11 generated by the orientation flat provided on the semiconductor wafer W is also covered. In addition, since the wafer back surface protection sheet 14 is formed of a fluorine resin film, particles are hardly generated from the protection sheet 14 itself, and particles can be prevented from adhering to the semiconductor wafer W. Further, since the fluorine-based resin film has a small amount of released gas, it can be avoided that the semiconductor wafer W is contaminated by the outgas from the wafer back surface protection sheet 14 and the quality of the wafer is deteriorated.

  The pressing member 13 has a plurality of leg portions 13b that are ejected outward from the central portion 13a. The central portion 13a and the leg portions 13b are formed to be curved as a whole, and cross the central portion 13a and the leg portion 13b. The cross section is arcuate. In addition, the pressing member 13 has a displacement between the center portion 13a and the tip of the leg portion 13b between the wafer back surface W2 and the inner wall surface 12a of the lid member 12 when the lid member 12 is engaged with the wafer housing member 11. It is shaped to be larger than the height of the space to be formed.

  Therefore, when the wafer accommodating member 11 and the lid member 12 are engaged, the central portion 13a of the pressing member 13 is pushed by the lid member 12, and the semiconductor wafer W of the semiconductor wafer W is passed through the wafer back surface protection sheet 14 at the tip of the leg portion 13b. The peripheral edge will be pressed.

  In this embodiment, the pressing member 13 having a bow shape in cross section is used, but a member having an elastic body sandwiched between the upper surface portion and the bottom surface portion may be used. Further, the portion pressed by the pressing member may be a part of the peripheral edge portion of the back surface protection sheet as in the present embodiment or the entire surface of the back surface protection sheet. In particular, when a pressing member configured to press the entire surface of the back surface protection sheet is used, the pressing member and the back surface protection sheet can be bonded in advance.

  According to the present embodiment, when the semiconductor wafer W is accommodated in the wafer storage container 10 and the storage container 10 is packaged with the laminate bag and the inside of the bag is replaced with the inert gas, the air flow is generated and the wafer is stored. Even if particles enter the container 10, the particles are captured by the wafer back surface protection sheet 14, so that the particles do not adhere to the semiconductor wafer back surface W 1. Further, even if a gap is generated at the orientation flat position provided on the semiconductor wafer W, the particles that have entered the wafer storage container 10 cannot wrap around the wafer surface side, so that the particles adhere to the semiconductor wafer surface W1. Nor.

  Note that the size of the wafer storage container 10 is not limited, and a wafer according to the size of the semiconductor wafer W to be accommodated, for example, a dome-shaped recess 11a having a diameter slightly larger than the diameter of the semiconductor wafer W may be used. Good.

(Second Embodiment)
FIG. 3 is a perspective view schematically showing a semiconductor wafer storage container according to the second embodiment, and FIG. 4 is a sectional view thereof.
The configuration of the wafer storage container 10 according to the second embodiment is almost the same as that of the first embodiment, and the same members are denoted by the same reference numerals. In the second embodiment, the wafer surface protection sheet 15 as a wafer surface protection member is provided between the semiconductor wafer W and the dome-shaped recess 11a when the semiconductor wafer surface W1 is disposed toward the dome-shaped recess 11a. The point differs from the wafer storage container 10 of the first embodiment.

  The wafer front surface protection sheet 15 is made of a 200 μm-thick fluororesin film like the wafer back surface protection sheet, has substantially the same shape as the inner wall surface of the dome-shaped recess 11a, and is in close contact with the dome-shaped recess 11a. As a result, the space formed between the semiconductor wafer W and the dome-shaped recess 11a is made as small as possible. Therefore, the thickness of the wafer surface protection sheet 15 is not particularly limited, but it is desirable to increase the thickness so that the holding performance of the semiconductor wafer W is not lost.

  That is, on the front side of the semiconductor wafer W, in order to prevent particles from being generated due to friction or the like due to the wafer surface W1 coming into contact with other members, the peripheral edge of the wafer is formed by the dome-shaped recess 11a of the wafer containing member 11. The wafer surface W1 is held open. For this reason, a larger space is formed on the front surface side of the semiconductor wafer W than the back surface side of the wafer into which the pressing member 13 is inserted, so that it can be said that particles are likely to remain and are relatively easily attached to the particles. . Therefore, by providing the wafer surface protection sheet 15, the space formed between the semiconductor wafer W and the dome-shaped recess 11 a is reduced, and particles are prevented from remaining in the space.

  According to the present embodiment, since the space between the semiconductor wafer W and the dome-shaped recess 11a is smaller than that of the conventional wafer storage container, the possibility that particles remain on the surface side of the semiconductor wafer W is reduced. The surface of the semiconductor wafer W can be kept clean.

  Before and after the wafer storage container 10 according to the first embodiment and the second embodiment is used, the wafer storage container 10 is wrapped with a laminate bag, and the inside of the bag is replaced with an inert gas (for example, nitrogen). The result of measuring the amount of particles on the front and back surfaces of the wafer is shown.

  Specifically, first, particles on the front and back surfaces of the semiconductor wafer were measured (particle amount before packaging), the measured semiconductor wafer was accommodated in a wafer storage container, and the wafer storage container was placed in an aluminum laminate bag. Then, the laminate bag is put in a vacuum chamber, the inside of the chamber is decompressed, and then an inert gas such as nitrogen is introduced into the chamber, and the laminate bag is sealed by thermocompression bonding with the heater in the chamber. . Next, after leaving in this state for several hours (for example, 3 hours), the laminate bag was opened, the semiconductor wafer was taken out from the wafer storage container, and the amount of particles on the front and back surfaces of the wafer was measured (particles after packaging). Here, the particles on the wafer front surface were measured using a foreign matter inspection apparatus, and the particles on the wafer back surface were visually observed.

  Note that a 2 inch diameter InP semiconductor wafer was used as the semiconductor wafer, and a plurality of InP semiconductor wafers were measured. Moreover, the same measurement was performed using the conventional wafer storage container (refer FIG.5, 6) as a comparative example.

  Table 1 shows the average value of the particle density obtained by measuring the particles on the surface of the 50 InP semiconductor wafers with a foreign substance inspection apparatus, and targets particles having a particle diameter of 0.3 μm or more.

From Table 1, in the comparative example, the wafer surface particle density after packaging is increased by 0.16 particles / cm ² before packaging, whereas the wafer storage according to the first embodiment in which only the back surface protection sheet 14 is provided. When a container is used, the wafer surface particle density after packaging is increased only by 0.04 particles / cm ² . From this, it can be said that the wafer back surface protective sheet 14 can efficiently suppress adhesion of particles that enter when replacing with the inert gas to the wafer surface. Furthermore, when the wafer storage container according to the second embodiment provided with the front wafer surface protection sheet 15 is used, no change in the wafer surface particle density is observed before and after packaging, and the wafer enters when replacing with an inert gas. It can be said that the particles are almost completely suppressed from adhering to the wafer surface.

  Table 2 shows the average value of the number of particles on the wafer obtained by visually observing particles on the back surface of 20 InP semiconductor wafers, and targets particles having a particle diameter of about 0.1 mm or more. Here, since the particles adhering to the back surface of the semiconductor wafer do not significantly affect the quality of the semiconductor wafer, it is considered that the particles adhering to the wafer surface do not need to be evaluated more strictly and were observed visually.

  From Table 2, in the comparative example, the number of particles on the back surface of the wafer after packaging is 1.3 / wafer increased from that before packaging, whereas the first embodiment and the second embodiment in which only the back surface protection sheet 14 is provided. When the wafer storage container according to the embodiment was used, no change was observed in the number of particles on the back surface of the wafer after packaging. In other words, it can be said that the wafer back surface protective sheet 14 can almost completely suppress the particles that enter when replacing with the inert gas from adhering to the wafer back surface.

  From the above, according to the wafer storage container according to the present invention, when storing the semiconductor wafer in the wafer storage container, packaging the storage container with a laminate bag, and replacing the inside of the bag with an inert gas, Even if a flow occurs and particles enter the wafer storage container, it can effectively prevent particles from adhering to and contaminating the front and back surfaces of the semiconductor wafer, so the surface of the semiconductor wafer can be kept clean for a long period of time. can do. Therefore, the semiconductor device manufacturer can take out the semiconductor wafer from the wafer storage container and perform epitaxial growth on the surface of the semiconductor wafer as it is. Therefore, it is necessary to clean the wafer surface as a pre-process of epitaxial growth. Productivity can be improved.

As mentioned above, although the invention made by this inventor was concretely demonstrated based on embodiment, this invention is not limited to the said embodiment, It can change in the range which does not deviate from the summary.
For example, in the above embodiment, the wafer back surface protection sheet 14 and the wafer surface protection sheet 15 are formed of a fluorine resin film such as PTFE, but the material is not limited to this, and polyethylene, polypropylene, polyester, Alternatively, it may be formed of a material that does not easily generate particles such as vinyl chloride.

  Further, the shape of the pressing member is not limited to that described in the above embodiment. For example, as shown in FIG. 5, an elastic member 21 such as a leaf spring is provided on the surface opposite to the surface of the wafer back surface protection member 22 that is in close contact with the wafer, and the wafer back surface protection member 20 that also functions as a pressing member. It is good.

  Further, the type of semiconductor wafer to be accommodated is not limited, and it goes without saying that it can be applied as a storage container for semiconductor wafers other than InP.

Claims (5)

A wafer storage container for storing wafers for epitaxial growth each provided with an orientation flat at the periphery, a wafer storage member having a dome-shaped recess capable of holding the wafer in contact with the periphery of the wafer; A lid member that can be engaged with the wafer accommodating member to seal the wafer accommodating portion, and is further molded into substantially the same shape as the opening of the dome-shaped recess, with the surface facing the dome-shaped recess. A wafer back surface protection member that is in close contact with the entire back surface of the mounted wafer and covers a gap between the wafer holding member and the wafer housing member generated by the orientation flat; and an inner wall surface of the dome-shaped recess, and having substantially the same shape, And a wafer surface protection member that comes into close contact with the concave portion and contacts the peripheral edge of the wafer.   A pressing member that is disposed between the wafer back surface protection member and the lid member and is pressed by the lid member when the wafer housing member and the lid member are engaged to press the wafer against the wafer housing portion; The wafer storage container according to claim 1.   The said wafer back surface protection member has a function as a pressing member which is pressed by the said cover member and presses a wafer to the said wafer storage part when the said wafer storage member and the said cover member are engaged. Item 14. A wafer storage container according to Item 1.   4. The wafer storage container according to claim 1, wherein the wafer back surface protection member is formed of a material that hardly generates particles, such as polyethylene, polypropylene, polyester, or vinyl chloride. 5.   5. The wafer storage container according to claim 1, wherein the wafer back surface protection member is formed of a material having a small amount of released gas, such as a fluorine resin film.

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